Wire gripping means for electric wiring devices



July 5, 1960 R. H. BENTLEY 2,944,242

WIRE GRIPPING MEANS FOR ELECTRIC WIRING DEVICES Filed April 15, 1957 INVENTOR.

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7 Patented July *5, 1960 Ere WIRE GRIPPING lVIEANS FOR ELECTRIC WIRING DEVICES Robert H. Bentley, Hartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation .of Connecticut Filed Apr. 15, 1957, Ser. No. 652,881

Claims. c1. ass-9's This invention relates to wire attachment means for electric attachment plug receptacles and the like Although the invention is shown in connection with a duplex plug receptacle, it will be understood that the invention is not limited to use with duplex receptacles, but is useful with wiring devices generally.

Due to increase in labor costs as well as the do-it-yourself vogue, the need has become intensified for easier and quicker attachment ofwires to electric devices than is alforded by screw type terminals. A number of devices for such purposehave appeared on the market, but the need to reduce the costs and increase the reliability of securing of the wire or wires has persisted.

Therefore, an object of this invention is to provide an improved means for attaching wires to electric devices, and particularly electric attachment plug receptacles, which will enablea quick, firm and unyielding connection of the wire, by a gripping member which may be readily stamped from sheet metal in one stamping operation.

Another object of the invention is to provide a jaw or strut for securing wires in the receptacles or other wiring devices, which may flex to permit the insertion and gripping of a wire, but is substantially rigid in its gripping action on attempt to withdraw the Wire.

Another .object of the invention is to provide an improved wire attaching means having. the aforesaid characteristicswhich can also be flexed to. release the wires by insertion of a releasing tool.

Other objects and advantages of the invention will appear as it is described in connection with the accompanying drawings.

In the drawings:

Fig. 1 is a plan view, partly broken away, of a device embodying the invention.

Fig. 2 is a perspective view of the wire gripping member used in Fig. 1.

Fig. 3 is a fragmentary transverse section view taken along line 3-3 of Fig. 1.

Fig. 4 is a transverse section view taken along line 4-4 of Fig. 1.

Referring to the drawings, the invention is shown as applied to an attachment plug receptacle of the duplex type. A two-part body of molded insulating material comprising cover and base portions and 12 is hollowed out with symmetrical recesses on each side of a longitudinal center line to receive identical metal contact members 20, 20', one on each side of a central partition 16. Each contact member has pairs of spaced spring fingers 22 on each end positioned to lie under conventional parallel slots provided in the cover member. The slots are in pairs on each end of the cover to receive parallel prongs of a conventional attachment plug which, on insertion through the slots, engage the spring fingers in usual fashion as in other attachment plug receptacles.

The spring finger or contact portions 22 on each end of the members are joined by a bar portion 24 formed integrally therewith and running longitudinally of the body 12 and lying flatwise alongside the inside surface of the outside wall of the body so as to'be backed up by the wall when pressure is applied to the bar portion, as will presently appear. i

To hold the bared end ofconductor wire 50 against the bar portion -24, an E-shaped gripping member 30 stamped from sheet metal is provided and lies centrally on the floor of the body 12 midway between the contacts 22. Preferably the material of which the gripping member is made is harder than the wire it is to grip. Since identical gripping members are provided for cooperation with each contact member, description of one will sufiice. The outer parallel legs 31 of the wire gripping member constitute jaw portions extending laterally from the ends of the connecting bar portion 33. The ends of the jaws 31 are tapered to a truncated end for biting into a conductor wire inserted between the said end and a channel or groove 26 formed in the connecting portion 24 running from back to front of the body 12. In order to insert the wire, holes 14' are for-med in the floor of the body 12 in substantial alignment with each of the channels or grooves 26.

Since the insertion of the wire tends to push up the jaws, the gripping member is held down at both sides in the following ways. A pair of small spaced lugs 34 extend laterally from the edge of the connecting portion 33 opposite the jaws 31 and into pockets 12;: formed in the central partition 16 of the body 12, and serve to hold on the floor the connecting portion side of the gripping member. On the other side of the gripping member the free end of the central leg 35 is inserted under the lower or inner edge of the connecting bar' portion 24 of the contact member and between it and the floor of the body. Preferably a finger is formed on the lower or inner edge of the connecting bar 24 over the leg 35 by forming two cuts or slots in that edge so that the finger can extend into a small rectangular aperture 38 in the leg 35'. The engagement of the finger in the aperture holds the gripping member 30 from sidewise movement over the floor of the body. At the same time, the engagement of the leg 35 with the bar portion 24 prevents movement of the bar portion forwardly.

The cover 10 rests upon the top edge of the connecting bar part 24 and holds the contact members 20, 20' in place in the base. The cover may be secured to the base by any conventional means such as screws (not shown) entering into the underside of the cover from the bottom of the base through bores 19 in the base or body 12.

Since the material of which the wire gripping member 30 is formed is preferably relatively stiff and only slightly resilient, greater flexibility is imparted to the wire gripping arms 31 by punching openings running lengthwise of the jaws to remove suficient metal to impart the desired flexibility of the jaws. The jaws are preferably inclined slightly upward from the floor of the body so that as the pull is increased on the wire, the jaw is forced against the central partition 16 which, being rigid, will rigidly support the jaw as a substantially rigid strut. At such time the jaw does not flex to any noticeable or substantial extent since the stress imparted thereto is almost entirely along its length with no significant lateral component. Thus, the greater the pull upon the wire the more firmly will the end of the jaw bite into the wire.

In order to release the wires when desired, slots 18 are formed under the midportion of each jaw in the floor of the base for insertion of a screwdriver or other implement. Upward pressure is imparted to the jaw by engagement of the end of the screwdriver or implement with the central portion of the jaw while the gripping member is otherwise rigidly held in place by the lugs 34 and securing leg 35.

a 2,944,242 a A lfa'vingidescribed. the; invention with a desire to secure Letters Patent, what is claimed is:

1. In an electric wiring device, a conductive member to which a wire is to be connected, an insulating body comprisingga cover and a-base, 'said'basebeing hollowed out forgthe reception of said conductive member and pro vidingginterior floor and side surfaces, said .cover holding said conductive member in'place in-the base a sheet metal, wire grippingrnember. having a leg portion with" at leastlaapart thereof beingflatand lying .on the floor of said. basesaidrbase having, a portion overlyingand holds ihgsaid wire grippingmemberadjacentaone endof said legrportiomuthe. other-end .of saidfleg portion underlying,

andzbeingheldibysaid'conductive'member, said wire grip; ping member having; ajaw portion alongside and laterally spaced from. one edge of said leg portion. ahdhavingyan endfladjacentsaidconductivememberto grip a wire insorted. between the two, said legportion, beingi'joined to said ljaw portion lying ontthe floor of said base. by a connecting portion and holdingsaid jaw portion in wire gripping, position, and said jaw.- portion. being-inclined from said interiorlsurface of said. body and bendable toward saidinterior surface as an outward pull is exerted on the wire .to ,more tightly grip the wireas the pull increases 2;. In=-an:-. electric wiring device, a'conductive member to which a Wire is to be connected, an insulating; body hollowedxout .forthe reception of said. conductivemember,.,ai sheetmetal. wire gripping member stamped into E-shape, lugs extending from the longitudinal edge of said grippingmember. into engagement with said-body, means holdingithefend of the'central leg of'saidtgrippingmember whereby -said-central. leg is' prevented from. moving atabothsitszends the end legs of said gripping; member. comprising-jawsshaving their ends engaging said conductiyenmember to grip the wires inserted between either jaw andesaidconductive member, said jaws being-inclined fromzanv. interior surface ofthe body and bendable toward that surface as 'an'outward pull is exerted on the wire tormoretightly grip the wire asthepull increases.

3; In, an electric wiring device, a' conductive member to which a-wire is to; beconnected, anrinsulatingbody hollowed: out: for the reception; of said: conductive member,a:.a sheet metal wiregripping-member stamped into Ei-fshape, lugs extending from-the longitudinal edge of said grip'pingmember" into engagement with said body;

said conductive member "overlying and holding" the "end of the central leg of the gripping member whereby said central leg is prevented from moving at both its ends, the end legs of said gripping members comprising jaws'having their ends adjacent said conductive member to grip wires inserted between either jaw and said conductive member, said jaws being inclined fromthe interior surface of said body and bendable toward that surface as an outward pull is exerted on the wire to more. tightly grip' theiw-ire as the pull increases.

4, In an electric wiring device, a conductive. member to which a'wire .is'to be connected," an insulating body hollowed out for the receptionof said conductive memher and providing interior floor and side surfaces, a sheet metal wire-gripping memberhaving a leg portion held at both its ends against movement upwardly from the floor of said body, with at least a part thereof being flat and lying on the floor, said wire gripping member having a'jaw portion alongside'of said leg portion but laterally spaced from one edge of said leg, portion and having an endadjacent said conductive member to grip a'wirein! serted between the two, a connectingportion lyingonthe floor of said body joining said leg portion' to said jaw portion and holding said jaw portion in wire gripping position, a lugv extending fromsaid connecting portion into'engagement with the body and holding oneend of said. leg portion, and saidrjaw'portionagainst movement from the floor, and said jaw portion. being inclined from the floor and bendable at its other-end toward thefloor as anzoutwardzpnll. is exerted on the wire to more tightly grip the wire as the pull increases.

-5, Anelectric wiring device astclaimed in: claim 4 wherein the holding of: theother endoflsaid leg-portion is by said other endrofrtlie leg; portion underlying and being held. by said conductivermember.

References Cited in thefile of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noa 2344 242 July 5, 1960 Robert H, Bentley It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line l9 strike out "lying on the floor of said base" and insert the same after "portion", first occurrence in line 2O same column 3.,

Signed and sealed this 4th day of April 1961.,

(SEAL) Attest: ERNEST W. SWIDER WXXPQXNK ARTHUR w. CROCKER Attesting Officer Acting Commissioner of Patents 

